1. Field of the Invention
This invention relates to expansion means for portable computers such as laptop and palmtop computers as well as for various other intelligent electronic devices, and more particularly, to a power-on protective structure for expansion cards installed in a portable computer or the like, which allows the replacement of the expansion cards installed in a portable computer or the like to be carried out only when the power supplied to the expansion cards is disconnected. This feature allows the data stored in the expansion cards not to be damaged or lost due to inadvertent detachment of the expansion cards from the portable computer while the power is still on.
2. Description of Related Art
Portable computers are now made increasingly smaller in size with more integrated functionality. Since a portable computer is smaller in size, the inside space is usually not large enough to accommodate all the required function modules therein. As a solution to this problem, a portable computer is typically provided with various expansion means that allow the portable computer to be installed with additional function modules provided on expansion cards, such as memory cards, hard drive cards, and so on. In general, the casing of the portable computer is formed with a receptacle in which expansion slots are provided so as to allow for easy replacement of the expansion cards. In replacing expansion cards, it is required that the replacement be made while the power supply to the expansion cards is disconnected; otherwise, it may cause damage to or data to be lost from the expansion cards.
One conventional solution to the foregoing problem is to provide a power detection device in the receptacle of the expansion cards that can detect whether or not the power system of the portable computer is turned off when the user wishes to remove the installed expansion cards in the portable computer. If the power is still on, the power detection device will send out a trigger signal to the power supply to turn off the power, allowing the user to replace the expansion cards under a power-off condition. This allows the replacement of the expansion cards to be carried out only when the power is turned off.
The foregoing power detection device, however, has several drawbacks. First, in the event that the power detection device fails for any reason, it will cause the user to replace the expansion cards under a power-on condition that would, as mentioned before, cause damage to or data to be lost from the expansion cards. There exists, therefore, a need for a new means that can ensure that the power is definitely off while replacing the expansion cards. Second, in the event that the portable computer accidentally falls to the ground, the power detection device can be damaged and thus become no longer functional. If any of the expansion cards is knocked out of the installed position from the receptacle under power-on conditions, it will cause damage to or data to be lost from the expansion cards. Third, the power detection device is high in manufacturing cost making it less competitive on the market.